Heat sensitive reproduction material and mbthod of using same



March 6, 1962 0. s05 ETAL 3,024,362

HEAT SENSITIVE REPRODUCTION MATERIAL AND METHOD OF USING SAME Filed July 16, 1959 HEAT. SENSITIVE LAYER POLYKETOHYDRINDENE AMINO COMPOUND FIG.I RESIN BINDER HEAT RAYS TRANSPARENT BASE SHEET I ,IIII

'TRANSPARENT BASE "'HEAT SENSITIVE LAYER ORIGINAL FIG. 2

ORIGINAL HEAT SENSITIVE LAYER TRANSPARENT BASE FIG. 3

ORIGINAL r TRANSPARENT BASE HEAT SENSITIVE LAYER FIG. 4

AMINO CARBOXYLIC ACID, POLYKETOHYDRINDENE, CYCLIZED RUBBER BINDER, F|G.5 MIXED IN BALLMILL FORMING HEAT SENSITIVE MATERIAL HEAT SENSITIVE MATERIAL COATED ON TRANSPARENT PAPER BASE DRIED AT ROOM TEMPERATURE IN V EN TOR.

OSKAR sIIs BY MARTIN GLOS United States Patent 3,024,362 HEAT SENSITIVE REPRODUCTION MATERIAL AND METHOD OF USING SAME Oskar Siis, Wiesbarlen-Biebrich, and Martin Glos, Wiesbaden, Germany, assignors to Kalle Aktiengesellschaft, Wiesbaden-Biebrich, Germany, a corporation of Ger- Filed July 16, 1959, Ser. No. 827,426 Claims priority, application Germany Aug. 9, 1958 11 Claims. (Cl. 250-45) This invention relates to a heat sensitive reproductionmaterial. More specifically, it relates to a novel composition including a heat sensitive substance which is coated on a base sheet material to form a reproduction material suitable for copying varied types of documents. Heat sensitive reproduction materials of this general type are already known. However, the image quality obtained with the commercially available reproduction materials leaves much to be desired. The principal object of'the present invention is an improved heat sensitive reproduction-material.

FIGURE 1 is an elevation of the heat sensitive mate-- rial under the original document with the heat sensitive FIGURE 5 is a flow diagram showing the steps in the manufacture of the heat sensitive material.

The. new heat sensitive reproduction materials of the present invention contain in the heat sensitive layer a polyketo-hydrindene in combination with an amino carboxylic acid or a salt formed by the-reaction of a primary amine with an organic carboxylic acid or sulfonic acid. Under the influence of heat the polyketo-hydrindene reacts with the amine salt or the amino carboxylic acid to form a dyestulf which is probably analogous to a Schiflfbasc.

Polyketo-hyd'rindenes which are useful in accord with v the present invention include for example:

Anhydro-bis-l ,3-diketo-hydrindene I 1,3-diketo-hydrindenc 1,2,3-triketo-hydrindene Bromo-anhydro-bis-l,3=diketo-hydrindene Examples of primary amines which can be used are:

Aniline 4-amino-toluene 4,4'-diamino-diphenyl-methan 4-amino-diphenyl 4-amino-diphenylamine 4-arnino-l-methoxy-benzene 4-amiuo-1-ethoxy-benzene n-Hexylamine n-Octylamine gumbo-pyridine v i g i following are examples of useful organic carboitylie'aeidsandprganicstufonicacids:-

3,024,362 Patented Mar. 6, 1962 2 Acetic acid Substituted acetic acids, such as Chloro acetic acid Bromo acetic acid Cyano acetic acid Phenyl acetic acid Bromo propionic acid Cinnamic acid Maionic acid Benzoic acid usNaphthalenesulfonic acid 4-toluene-sulfonic acid ice Examples of amino-carboxylic acids'are:

fl-(3'-aminophenyl)-propionic acid 4-amino-benzoic acid ages do not change their color nor do their contrasts decrease in quality,:so'that they can be stored for longer periods.

The heat sensitive layers of the present inventionmay be obtained from a coating composition which is prepared as follows:

The polyketo-hydrindenes and the amine salts or amino 9 carboxylic acids, are mixed in the form of fine suspen- The mixture.

sions with a solution of a binding agent. is then applied to a base material and the layer is dried. Advantageously, drying is elfected at room temperature, without heating.

The drying process may be speeded up by passing an air current over the'coated side of the sheet. Moderate heating of the layer or the air current may be considered, but the temperature applied should not exceed 35-40 C.

If a salt of a primary amine is used, it need not be isolated before its application. Also layers of equally high quality are obtained when the amine and the acid component are dispersed separately in the coating solution.

The reactive components may be applied with a binding agent. Suitable binding agents are resins that are' soluble in solvents, which do not dissolve the dyestuffforming components, for example, aliphatic hydrocarbons, and some halogenated hydrocarbons. Resins that are suited to be used as binding agents are, for example, cyclized rubber, such as the product sold by Messrs. Chemische Werke Albert, Wiesbaden-Biebrich, Western Germany, under the registered trademark Alpex 45.0

J, maleic resins, such as the KM- and KPM-resins of J Messrs; Badische Anilinund Sodafabrik A.G., Ludwigshafen, Western Germany, and modified rosin esters, such as the product also sold by Messrs. Badische Anilinund Sodafabrik AG, Ludwigsha'fen, under the registered trademark Laropal" B.

It is not necessary for the components required in the heat sensitive layers to be present in stoichiometric quantities. The proportions of the various components contained in the mixture 'can be varied to ,a wide degree, but a proportion of from 5 to 8 parts by weight of amino component to 1 part by weight of polyketohydrim time component has proved to be of advantage. The quantity of resin present in layer may also vary and de-' oaths kind of resin alsed. lngeneral, the quantity of the resin should amount to about half of the quantity of the amino component present.

Suitable base sheet materials for the heat sensitive reproduction layers of the present invention are: glass, paper, transparent paper, cellulose hydrate films, transparent plastic films, e.g. polyvinylchloride films, cellulose acetate films and polyethylene terephthalate films and other solid substances in the form of films or plates which are preferably permeable to light rays.

The heat sensitive reproduction materials of the present invention may be used according to either of the following processes:

(1) The material provided with a heat sensitive layer is placed with its coated side in contact with the original to be copied, which may be an original having a written or printed image on one or both sides. Through the back of the reproduction material radiant heat is applied to the heat sensitive layer, e.g. by means of an infra-red lamp. The more intense the source of energy used, the sharper are the contrasts of the image produced and the shorter is the time of radiation required. By this treatment a deeply colored, direct, reversed image of the original is produced in the heat sensitive layer, which may be read from the back. of the transparent base material as a right reading image.

(2) Originals with only one side printed or written upon may be copied, alternatively, by radiating heat through theoriginal which is placed in contact with the heat sensitive layer. In this case it is immaterial whether the heat sensitive layer is in contact with the front side or the back of the original.

The duration of the heat action which is required for the production of faultless, sharp images, that are rich in contrast cannot be generally stated, but must be determined in each case. It depends on a number of factors, such as the kind and intensity of the source of energy used, its distance from the original, the kind of base material and the composition of the heat sensitive layer.

The reproduction material of the present invention may also be used for the production of images by means of a heated image forming member such as a heated stylus or stamp.

Examples (1) 20 grams of aniline chloroacetate are intimately mixed in a ball mill with 200 cc. of ligroin and the mixture is then mixed with 4 grams of finely pulverized anhydro-bis-l,3-diketo-hydrindene. To this suspension there are added lOO cc. of a solution in ligroin of a cyclized rubber, e.g. the product sold by the Chemische Werke Albert, Wiesbaden-Biebrich under the registered trademark Alpex" 450 J. The mixture is once more intimately mixed. Thereafter the mixture is coated in known manner onto transparent paper and the layer which forms is dried at room temperature. If the layer thus obtained is heated to a temperature of 90 to 100 C., its light yellow color changes quickly to a dark blue. This phenomenon can be used for the production of an image by the following process:

The coated transparent paper is placed with its coated side incontact with the original to be copied, e.g. a printed page of a book and then the back of the transparent paper is exposed to the radiations of a powerful infra-red lamp. The infrared radiations penetrate through the uncoated side of the heat sensitive copying paper and are strongly absorbed by the printed areas of the original. The heat thus absorbed causes a change in color in those parts of the heat sensitive layer which are in contact with the printed areas of the original. A reversed directimage of the original in a dark blue color is obtained which is readable from the back of the transparent paper as a right reading image.

The same result is obtained when the aniline chloroaeetate just used is replaced by fi-(3'-amino-phenyl)- propionic acid. Equallygood results are obtained if instead of aniline chloroacetate, 4-amino-diphenyl chloroacetate, is used, but in this case it is recommended to use a somewhat higher developing temperature (about C.).

Bromo-anhydro-bis-l,3-diketohydrindene and either 4- amino-diphenylamine benzoate or Z-amino-pyridine chloroacetate may also be used to form a heat sensitive layer which will give brownish-black copies of an original, if the copying method described above is followed and sufficient heat is supplied. Another heat sensitive layer according to the present invention, which contains anhydro'bis-l,B-diketohydrindene and benzylamine malonate produces reddish-violet images if the same copying process is followed. When the heat sensitive layer contains a mixture of anhydro-bis-l.B-diltetohydrindene, 4,4- diamino-diphenylmethane and tit-naphthalene sulphonic acid brownish black copies are obtained.

(2) To a suspension of 12 grams of most finely ground 4-amino-l-ethoxy-benzene chloroacetate in 150 cc. of gasoline, there are added 2 grams of equally finely pulverized triketohydrindene and 50 cc. of a 10 percent solution in gasoline of an acrylic resin, e.g. the product sold by Messrs. Rohm and Haas, Darrnstadt, under the registered trademark Plexigum" P 26. The combined components are intimately mixed and the mixture obtained is used for coating transparent paper in known manner. The layer thus formed is dried at 30 to 40 C. by heating the coated paper to about 110 C. its color changes from white to reddish-brown. If the heat sensitive paper thus prepared is used in a contact copying process as described in example, reddish-brown images of the original are obtained.

If the triketohydrindene just mentioned is replaced by 1,3-diketohydrindene and adequate heat influence is ensured, the color of the heat sensitive layer turns from a light brown to dark brown, which within a short time becomes a brownish black.

Dark brown images are also obtained when, in addition to 1,2,3-triketohydrindene, the heat sensitive layer contains benzylamine 4-toluene-sulfonate as the second dye-forming component.

A most finely ground suspension of 20 grams of benzylamine chloroacetate and 4 grams of anhydro-bis-l,3-diketo-hydrindene in 350 ml. of ligroin which contains also 10 grams of dissolved acrylic resin is coated onto paper or a plastic film and then dried at room temperature or moderately higher temperature.

By pressing a stamp or stencil heated to about C. onto the dried layer a positive, red violet impression on a light yellow background is obtained.

If the conventional writing device of a recording apparatus, e.g. a pressure indicator, a temperature recorder or a steam gauge, is replaced by a recording needle which is electrically heated to the above referred temperature, and a recording paper coated with a layer having the composition described in the preceding paragraph is used, the apparatus traces the measured values in a red-violet color on a light yellow background.

Having thus described the invention what is claimed is:

l. A heat sensitive reproduction material comprising a base sheet coated with a heat sensitive layer including a polyketohydrindene and a substance selected from the group consisting of amino carboxylic acids, salts formed from primary amines and organic carboxylic acids and salts formed from primary amines and sulfonic acids.

2. A heat sensitive reproduction material comprising a base sheet coated with a heat sensitive layer including a binding agent, a polyketohydrindene and a substance selected from the group consisting of amino carboxylic acids, salts formed from primary amines and organic carboxylic acids and salts formed from primary amines and sulfonic acids.

3. A heat sensitive reproduction material comprising atransparent base sheet coated with a heat sensitive layer including a polyketohydrindene and a substance selected from the group consisting of amino carboitylic acids, salts formed from primary amines and organic carboxylic acids and salts formed from primary amines and sulfonic acids.

4. A heat sensitive reproduction material comprising a base sheet coated with a heat sensitive layer including anhydro-bis-1,3-diketohydrindene and toluideine chloroacetate.

5. A heat sensitive reproduction material comprising a base sheet coated with a heat sensitive layer including bromoanhydro-bis-l,3-diketohydrindene and benzylamine chloroacetate.

6. A heat sensitive reproduction material comprising a base sheet coated with a heat sensitive layer including 1,2,3-triketohydrindene and 4-arnino-l-ethoxy-benzene chloroacetate. I

7. A heat sensitive reproduction material comprising a base sheet coated with a heat sensitive layer including 1,2- diketohydrindene and ,6-(3'-aminophenyl)-propionic acid.

8. A heat sensitive reproduction material comprising a base sheet coated with a heat sensitive layer including 1,2, 3-triketohydrindene and benzylamine malonate.

9. The method of making reproductions comprising placing a transparent base sheet coated with a heat sensitive layer including a polyketohydrindene and a substance selected from the group consisting of amino carboxylic acids, salts formed from primary amines and organic carboxylic acids and salts formed from primary amines and sulfonic acids with its coated side in contact with an original to be copied and applying radiant heat through said transparent base sheet to form an image of the original in said heat sensitive layer. Y

10.. The method of making reproductions comprising placing a base sheet coated with a heat sensitive layer including a polyketohydrindene and a substance selected from the group consisting of amino carboxylic acids, salts formed from primary amines and organic carboxylic acids and salts formed from primary amines and sulfonic acids in contact with an original to be copied and applying radiant heat through said original to form an image of said original in said heat sensitive layer.

11. The method of forming an image comprising bringing a heated image forming member into contactwith a heat sensitive layer including a polyketohydrindene and a substance selected from the group consisting of amino carboxylic acids, salts formed from primary amines and organic carboxylic acids and salts formed from primary amines and sulfonic acids coated on a base sheet in contact with an original to be copied.

References Cited in the file of this patent 

1. A HEAT SENSITIVE REPRODUCTION MATERIAL COMPRISING A BASE SHEET COATED WITH A HEAT SENSITIVE LAYER INCLUDING A POLYKETOHYDRINDENE AND A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF AMINO CARBOXYLIC ACIDS, SALTS FORMED 